Energy and position correction or adjustment in a scintillation position calculation apparatus is described in commonly assigned U.S. Pat. No. 5,410,153 to Feirrera. In such systems, second order corrections in position and energy values for scintillation events are added as a function of originally calculated position values.
In a scintillation camera, groups of photodetectors receive light from a slab-like scintillator crystal and the intensity signals from the photodetectors are used to calculate the exact position of the scintillation event. An image formed from a very large number of scintillations is used for medical diagnostics, as is known in the art.
For each scintillation event, the raw intensity values are analyzed to determine whether the scintillation represents a direct (unscattered) gamma photon resulting from radioactive nuclear decay of an isotope ingested in trace quantities by the patient.
Since the light sensitivity of the photodetectors is not perfectly uniform over the entire entry windows of the photodetectors, errors (variance) position calculation result as a function of the scintillation's position with respect to the photodetectors. In one conventional scintillation camera, the photodetectors are arranged in a hexagonal close packed array with substantially hexagonal entry windows. The resulting image shows a noticeable trace of the "honeycomb" pattern as an artifact characteristic.